Pavlos Kassomenos

Extreme temperatures have long been associated with adverse health impacts, ranging from minor illness, to increased hospitalizations and mortality. Heat-related mortality during summer months is likely to become an increasing public health problem in future due to the effects of climate change. We performed a health impact assessment for heat-related mortality for the warm months of April-September for the years 2004 to 2009 inclusive, for the city of Nicosia and for Cyprus as a whole, based on separately derived exposure-response functions. We further estimated the potential future heat-related mortality by including climate projections for southern Europe, which suggest changes in temperature of between 1°C and 5°C over the next century. There were 32 heat-related deaths per year in Cyprus over the study period. When adding the projected increase in temperature due to climate change, there was a substantial increase in mortality: for a 1°C increase in temperature, heat related mortality in Cyprus was estimated to double to 64 per year, and for a 5°C increase, heat-related mortality was expected to be 8 times the baseline rate for the warm season (281 compared with 32). This analysis highlights the importance of preparing for potential health impacts due to heat in Cyprus, particularly under a changing climate.

Four components of air pollution were identified by PCA in Karlsruhe and Potsdam.PMCOARSE production from secondary sources was indicated in Potsdam in warm period.Associations among slow moving air masses and increased PM10 levels were suggested.The residing areas of incoming air parcels are potential transboundary PM sources.This paper aims to decompose the profile of particulates in Karlsruhe and Potsdam (Germany), focusing on the localization of PM potential transboundary sources. An air mass cluster analysis was implemented, followed by a study of air mass residence time on a grid of a 0.5° × 0.5° resolution. Particulate/gaseous daily air pollution and meteorological data were used to indicate PM local sources. Four Principal Component Analysis (PCA) components were produced: traffic, photochemical, industrial/domestic and particulate. PM2.5/PM10 ratio seasonal trends, indicated production of PMCOARSE (PM10–PM2.5) from secondary sources in Potsdam during warm period (WP). The residing areas of incoming slow moving air masses are potential transboundary PM sources. For Karlsruhe those areas were mainly around the city. An air mass residence time secondary peak was observed over Stuttgart. For Potsdam, areas with increased dwelling time of the arriving air parcels were detected particularly above E/SE Germany.

ABSTRACT In this work, the emissions of four pollutants (CO, Benzene, NO<sub align="right">x and PM<sub align="right">10) during a working day were estimated and presented in main avenues of Athens, Greece with the aid of the COPERT methodology. The data used as input to the COPERT III was collected through a measuring campaign every 15 min and lane for the time period 07.30-17.30 of a weekday. The results revealed the CO, Benzene, NO<sub align="right">x and PM<sub align="right">10 patterns in main avenues of Athens, Greece during a typical working day.

... Chen, G., 2004: A 10-yr climatology of oceanic water vapor derived from the TOPEX Microwave Radiometer. ... Free, M., JK Angell, I. Durre, J. Lanzante, TC Peterson, and DJ Seidel, 2004: Using first differences to reduce inhomogeneity in radiosonde temperature datasets. ...

Ground-based spectroradiometric measurements were taken in the atmosphere of Athens during May 1995 in order to investigate various atmospheric conditions. This study focuses on the Ångström exponent α, which is the slope of the logarithm of the aerosol optical depth (AOD) versus the logarithm of the wavelength, lnλ, and is commonly used to characterize the wavelength dependence of AOD and to provide some basic information on the aerosol size distribution. Using the Volz method, Ångström exponent values, α, were derived in five narrow spectral bands, 340 380, 380 440, 440 500, 500 670 and 670 870 nm. Also using both Volz and least-squares fit methods α values were derived for the whole spectrum 340-870 nm.The results show that α depends strongly on the wavelength interval used due to the curvature of the lnAOD versus lnλ line. Using the spectral dependence of the Ångström exponent and the relationship between α computed in different spectral bands with AOD, an attempt to investigate on the aerosol types is made. The results obtained are rather contradictory and the determination of a dominant aerosol type in the Athens area is not clear. Nevertheless, in the most cases the anthropogenic aerosols seem to be the dominant type with rather significant contributions of coarse-mode particles due to particle growing or due to mixing processes with other aerosol types.

Summary¶In this study a methodology for grouping seasonal circulation types occurring over an area is introduced. This procedure combines the surface air mass characteristics affecting the area with the synoptic conditions prevailing over it. Factor Analysis and Cluster Analysis are used to derive the circulation types, based on surface meteorological data and surface pressure grid data. The methods are applied to Athens, Greece, using data over the period 1954–1999 for winter (December, January, February) and summer (June, July, August) seasons. The daily circulation types are analyzed at surface level and their temporal evolution is examined via transition matrices. 315 grid points are used covering the area between 25° N to 60° N and 10° W to 40° E. This analysis derives 8 circulation types for the winter and 4 for the summer.A reduction in cyclonic activity and an increase in anticyclonic activity in the Central Mediterranean are detected in the late 1980s and early 1990s during the winter period. During summer the etesian winds and the local flows are dominant over Athens.

ABSTRACT Southern Europe suffers from forest fires. The management of these disasters is of importance to both government authorities and the public. This article presents the results of a research project aimed at modeling forest fire events and producing fire risk maps. The mathematical model is embedded in an ArcView Geographic Information System (GIS) platform. The interface is in Visual C++ 6.0. The thematic and individual risk maps generated are merged into an integrated risk map. The assessment platform (model, GIS, data, decision support) was applied to the area of northern Evia Island, central Greece, using five different scenarios. The platform provides a tool for use by authorities to estimate risks for forest fire management. The model was specifically adapted for the Olympic Games of 2004, Athens, Greece.

In the framework of the COST733 Action "Harmonisation and Applications of Weather Types Classifications for European Regions" an evaluation of circulation type classifications (CTCs) for observed summer surface ozone concentrations is performed. First, the main characteristics of the circulation classification methodologies in terms of pattern frequencies are addressed using the baseline COST 733 catalogue (cat 2.0), a product of the new cost733class software. In a second step, the probabilistic Brier skill score is used to quantify the explanatory power of all classifications in terms of the maximum 8 hourly ozone concentrations exceeding the 120 μg/m3 threshold, this based on ozone concentrations from 130 Central European measurement stations. Evaluation results averaged over all stations indicate generally higher performance of CTCs with a higher number of types. Within the subset methodologies with similar number of types, there is no indication that a specific methodology (predefined thresholds, principal component analysis, leader algorithms and optimization algorithms) is superior in the overall skill score performance. This is further elaborated by exploring additional capabilities of the cost733class software. Sensitivity experiments are performed using different domain sizes, input variables, seasonally-based classifications and multiple-day sequencing. As an illustration, also conditioned (towards e.g. temperature) CTCs with various weights are derived and tested similarly. All results exploit a physical interpretation by adapting the environment-to-circulation approach, providing more detailed information on specific synoptic conditions prevailing on days with high surface ozone concentrations. Although this research cannot bring forward a favorable methodology for this kind of applications, the results presented here can provide a basic user support with respect to the cost733class software and the development of a more user- or application-specific CTC approach.

ABSTRACT The spatial distribution of PM sources affecting Athens (Greece) was determined by introducing in the Concentration Weighted Trajectory (CWT) algorithm PM2.5 concentration and composition data from an urban background site. The produced 0.5°×0.5° resolution maps clearly revealed the impact of anthropogenic and natural sources and the relative contribution of regional and transboundary emissions in PM2.5 mass. For sulfates, ammonium and organic carbon, a significant regional contribution derives from Northern airflows through Greece and Balkan Peninsula (mainly Bulgaria). Air masses incoming from North-West Africa, during Saharan dust outbreaks, and the Mediterranean, are charged with aerosol constituents from different combustion sources such as nitrates. Sea spray originates from the Ionian Sea and also from southern directions through Saronikos Gulf. The intrusion of Saharan dust is responsible for the concentration maxima of the elements of crustal/main crustal origin, and was almost exclusively associated with S-SW airflows through Algeria, Tunisia and Libya.

ABSTRACT The aim of this study was to identify local and exogenous sources affecting particulate matter (PM) levels in five major cities of Northern Europe namely: London, Paris, Hamburg, Copenhagen and Stockholm. Besides local emissions, PM profile at urban and suburban areas of the European Union (EU) is also influenced by regional PM sources due to atmospheric transport, thus geographical city distribution is of a great importance. At each city, PM10, PM2.5, NO2, SO2, CO and O3 air pollution data from two air pollution monitoring stations of the EU network were used. Different background characteristics of the selected two sampling sites at each city facilitated comparisons, providing a more exact analysis of PM sources. Four source apportionment methods: Pearson correlations among the levels of particulates and gaseous pollutants, characterisation of primal component analysis components, long-range transport analysis and extrapolation of PM size distribution ratios were applied. In general, fine (PM2.5) and coarse (PM10) particles were highly correlated, thus common sources are suggested. Combustion-originated gaseous pollutants (CO, NO2, SO2) were strongly associated to PM10 and PM2.5, primarily at areas severely affected by traffic. On the contrary, at background stations neighbouring important natural sources of particles or situated in suburban areas with rural background, natural emissions of aerosols were indicated. Series of daily PM2.5/PM10 ratios showed that minimum fraction values were detected during warm periods, due to higher volumes of airborne biogenic PM coarse, mainly at stations with important natural sources of particles in their vicinity. Hybrid single-particle Lagrangian integrated trajectory model was used, in order to extract 4-day backward air mass trajectories that arrived in the five cities which are under study during days with recorded PM10 exceedances. At all five cities, a significantly large fraction of those trajectories were classified in short- and medium-range clusters, thus transportation of particulates along with slow moving air masses was identified. A finding that supports the assumption of long-range transport is that, at background stations, long-range transportation effects were stronger, in comparison to traffic stations, due to less local particle emissions. Short-range trajectories associated to PM transport in Stockholm, Copenhagen and Hamburg were mainly of a continental origin. All three cities were approached by slow moving air masses originated from Poland and the Czech Republic, whereas Copenhagen and Stockholm were also influenced by short-range trajectories from Germany and France and from Jutland Peninsula and Scandinavian Peninsula, respectively. London and Paris are located to the north-west part of Europe. Trajectories of short and medium length arrived to these two megacities mainly through France, Germany, UK and North Atlantic.

ABSTRACT The amount of time air spends over a region is linearly related to the region's contribution in PM. The residence time of air masses over emission sources was the main criterion for the division in 15 regions-origins. Daily PM concentrations in Paris (France), were reconstituted by multiplying the air mass residence time for each-one of the 15 regions by a regression coefficient (Bk) expressing the ability of each region to enrich the daily PM concentrations. The comparison between observed and predicted values gave satisfactory results. Local regions contributed cumulatively more than 50% of PM2.5 and PM10 in an average daily basis, whereas the residing areas of air parcels were particularly located around the city. Due to the scarceness of eastern circulation, continental airflows were associated with few episodes of extreme aerosol contributions, whereas peak air mass residence time values were isolated above Germany.

Three years of hourly O3 concentration measurements from a metropolitan and a medium scale urban area in Greece: Athens and Ioannina respectively, were analyzed in conjunction with hourly wind speed/direction data and air mass trajectories, aiming to reveal local and regional contributions respectively. Conditional Probability Function was used to indicate associations among distinct wind directions and extreme O3 episodes. Backward trajectory clusters were elaborated by Potential Source Contribution Function on a grid of a 0.5°×0.5° resolution, in order to localize potential exogenous sources of O3 and its precursors. In Athens, an increased likelihood of extreme O3 events at the Northern suburbs was associated with the influence of SSW-SW sea breeze from Saronikos Gulf, due to O3 transportation from the city center. In Ioannina, the impacts of O3 conveyance from the city center to the suburban monitoring site were weaker. Potential O3 transboundary sources for Athens were mainly l...

Detailed traffic data collected from seven major roads in the city of Athens, Greece are presented and analysed in this study. Vehicles are split into seven categories while vehicle speed is also recorded. Based on these data the emissions of five major pollutants (CO, Benzene, NO(X), PM(10) and VOCs) were calculated with the aid of the COPERT methodology and, based on these results, an Artificial Neural Network was also developed. The results of the two methodologies were compared and it was found that the differences were very small. The ANN model seems to be a reliable alternative to calculate road traffic emissions in a busy road environment. The results reflect the spatial and temporal distribution of the concentrations of the pollutants examined. Alternative "what if" scenarios of the fleet distribution were also applied by means of environmental policy. Since Athens experiences low air quality conditions the correct estimation of traffic emissions is crucial since t...

In this work an approach is presented that describes the changes of benzene concentration in the air, in relation with the special traffic characteristics of a road. The dominant input parameters of the model are traffic density and the vehicle's type distribution according to seven main categories characterized by different emission factors. The dispersion approach used is a semi-empirical relationship that apart from emission rates requires also wind speed and the direction, as well as the geometrical characteristics of the road. The methodology was validated for Ioannina, a Greek medium sized town with special traffic and geographic characteristics presenting high atmospheric pollution values. It is found that the benzene concentrations estimated by the methodology are in a very good agreement with the measurements.

The fraction of meteorological information available at each part of the Greek Archipelago is examined in this study. The area is of primary importance regarding meteorological information since it gathers the main tourist activity of the country. The key parameter in this investigation is the transmission coefficient of information (TCI), which demonstrates the coverage of the area with meteorological information

In the framework of the COST733 Action "Harmonisation and Applications of Weather Types Classifications for European Regions" an evaluation of circulation type classifications (CTCs) for observed summer surface ozone concentrations is performed. First, the main characteristics of the circulation classification methodologies in terms of pattern frequencies are addressed using the baseline COST 733 catalogue (cat 2.0), a product of the

The generation of a typical meteorological year is of great importance for passive solar architectural applications. In this context, within the PASCOOL project, a software tool has been developed, utilizing the Filkenstein-Schafer statistical method for the creation of a typical meteorological year. Using this software tool, a typical meteorological year was generated for Athens, Greece. The data used were from

The main objective of this paper was to identify possible acute heat-induced summer mortality in five regions of England namely the Yorkshire and the Humber, West Midlands, North East, North West and South East regions and reveal associations with specific air flows. For this purpose, backward air mass trajectories corresponding to daily episodes of increased temperatures were produced and divided to clusters, in order to define atmospheric pathways associated with warm air mass intrusions. A statistically significant at 95 % confidence interval increase in daily total mortality (DTMORT) was observed during the selected episodes at all five regions and thus, heat-induced mortality was indicated. The calculated raise was more intense in the West Midlands, North West and South East regions, whereas the results in the North East and Yorkshire and the Humber regions were less evident. Large fractions of thermal episodes, elevated average temperature values and higher average DTMORT levels were primarily associated with the short-medium range South West (SW) and/or East-South East (E-SE) trajectory clusters, suggesting relations among heat-induced mortality and specific atmospheric circulations. Short-medium length of SW and E-SE airflows, calculated by an application of Haversine formula along the centroid trajectory of each cluster, implies the arrival of slow moving air masses. Atmospheric stagnation could enhance human thermal stress due to low wind speed.

ABSTRACT Particulate air pollution is associated with adverse health effects to the population exposed. The aim of this paper is the identification of local and regional sources, affecting PM10 and PM2.5 levels in four large cities of southern Europe, namely: Lisbon, Madrid, Marseille, and Rome. Air pollution data from seven sampling sites of the European Union network were used. These stations were selected due to their ability of monitoring PM2.5 concentrations and providing reliable series of data. Each station’s background was also taken into account. Pearson correlation coefficients and primal component analysis components were extracted separately for cold and warm periods in order to define the relationships among particle matters (PMs) and gaseous pollutants (CO, NO2, SO2, and O3) and evaluate the contributions of local sources. Possible seasonal variations of PM2.5/PM10 ratio daily values were also used as markers of PM sources, influencing particulate size distribution. Particle emissions were primarily attributed to traffic and secondarily to natural sources. Minimum daily values of PM2.5/PM10 ratio were observed during warm periods, particularly at suburban stations with rural background, due to dust resuspension and also due to the increase of biogenic coarse PM (pollen, dust, etc.). Hybrid Single-Particle Lagrangian Integrated Trajectory Model trajectory model was used in order to compute the 4-day backward trajectories of the air masses that affected the four cities which are under study during days with recorded PM10 exceedances, within a 5-year period (2003–2007), at 300, 750, and 1,500 m above ground level (AGL). The trajectories were then divided to clusters with a K-means analysis. In all four cities, the influence of slow-moving air masses was associated with a large fraction of PM10 exceedances and with high average and maximum daily mean PM10 concentrations, principally at the 300 m AGL analysis. As far the issue of the increased PM10 concentrations, the results were weaker in Marseille and particularly in Rome, probably due to their greater distance from Northwest Africa, in comparison to Madrid and Lisbon. Dust intrusions from the Sahara desert and transportation of Mediterranean/Atlantic sea spray, were characterized as primary regional sources of exogenous PM10 in all four cities. Continental trajectories from the industrialized northern Italy affected PM10 levels particularly in Marseille and Rome, due to their more eastern geographical position.

This paper analyzed air quality in six cities in Southern Germany (Ulm, Augsburg, Konstanz, Freiburg, Stuttgart and Munich), in conjunction with the prevailing synoptic conditions. Air quality was estimated through the calculation of a daily Air Stress Index (ASI) constituted by five independent components, each one expressing the contribution of one of the five main pollutants (PM10, O3, SO2, NO2 and CO) to the total air stress. As it was deduced from ASI components, PM10 from combustion sources and photochemically produced tropospheric O3 are the most hazardous pollutants at the studied sites, throughout cold and warm periods respectively, yet PM10 contribute substantially to the overall air stress during both seasons. The influence of anticyclonic high pressure systems, leading to atmospheric stagnation, was associated with increased ASI values, mainly due to the entrapment of PM10. Moderate air stress was generally estimated in all cities however a cleaner atmosphere was detected principally in Freiburg when North Europe was dominated by low pressure systems. Daily events of notably escalated ASI values were further analyzed with backward air mass trajectories. Throughout cold period, ASI episodes were commonly related to eastern airflows carrying exogenous PM10 originated from eastern continental Europe. During warm period, ASI episodes were connected to the arrival of regionally circulated air parcels reflecting lack of dispersion and accumulation of pollutants in accordance with the synoptic analysis.